Logitech nano receiver teardown (USB DONGLE)

[sdttn]

The chip (NRF LU1P18)  from nordicsemi.
http://www.nordicsemi.com/eng/Products/2.4GHz-RF/nRF24LU1P


http://img708.imageshack.us/img708/872/dscf1117n.jpg


http://img72.imageshack.us/img72/338/dscf1118y.jpg


http://img259.imageshack.us/img259/3795/dscf1119ei.jpg


http://img829.imageshack.us/img829/8793/dscf1120r.jpg

The links for larger images.

[Psi]

For reference/comparison, here's what the cheap Deal Extreme bluetooth receiver looks like

Dunno what the IC is, cant read it.

[amyk]

That is a Conwise CW6626M.

(See page 24 of the datasheet, the pinouts agree.)

[Mechatrommer]

is it that easy to build a USB + 2.4GHz trans ceiver?!

[lpc32]

Is that white component an antenna?

And can the firmware be read?

[Fraser]

White component = 2.4GHz SMD ceramic antenna. Very common in miniature Wi-Fi and Bluetooth modules and more predictable than PCB antennas on cheap FR4.

Aurora

[miguelvp]

I have a TrimSlice that came with a Bluetooth USB 2.0 Dongle, just plugged in in my system to see if Windows 7 recognized it and came up as CSR Bluetooth Chip. Device type: Bluetooth Radios, Manufacturer Realtek Semiconductor Corp.

Hardware ID: USB\VID_0A12&PID_0001&REV_0134

It looks the same as Psi but it's grey color, but I have not taking it apart. Internet searches for a Realtek Bluetooth USB 2.0 dongle shows them all with black plastic like Psi's.

Totally forgot about it until I saw the picture on this thread

I guess my desktop now has Bluetooth from now on

[janekm]

White component = 2.4GHz SMD ceramic antenna. Very common in miniature Wi-Fi and Bluetooth modules and more predictable than PCB antennas on cheap FR4.

Aurora

Well I would argue that the usual reason for using a ceramic chip antenna is the smaller size that can be achieved (since the active element is folded in 3D space inside the ceramic, and a material with much higher dielectric constant compared to FR-4 can be chosen to further shorten the wavelength). The efficiency of a small ceramic chip antenna is considerably worse than a decent-sized (i.e. much larger) PCB antenna even without perfect control over the FR-4 dielectric constant.

That tiny one on this dongle won't work great at all but it's enough for a mouse sitting next to the dongle or at most a few meters away.

[lpc32]

But it's not much of a size difference in the end. And it costs more.

[Fraser]

I have never used ceramic antenna as I always tend to use conventional monopole or dipole antenna and do not mess with PCB antennas very much in my transmitter designs. I found a useful little PDF that details antenna types and requirements.

I attach it for your information. I was wrong about the ceramic antenna being better for poor dielectric FR4 applications. Apparently they need careful use with a good dielectric substrate and ground-plane !

The only advantage I can see in them in small size.

I do not see me designing using ceramic antennas any time soon.

Aurora

[lpc32]

Thanks.

Now, if only someone tried modifying the firmware there...

[Deckert]

Hi,

Did a quick opening of my Logitech nano receiver as well. Seems mine is possibly older, because it uses two discreet chips:

NRF24L01 - Ultra low power 2.4GHz RF Transceiver IC
AT90USB162 - Atmel 8-bit micro

From their site:

Atmel 8-bit AVR RISC-based microcontroller combines 16KB ISP flash memory with read-while-write capabilities, 512B EEPROM, 512 bytes SRAM, 22 general purpose I/O lines, 32 general purpose working registers, two flexible timer/counters with compare modes and PWM, USART, programmable watchdog timer

http://www.atmel.com/devices/at90usb162.aspx

Oscillator and antenna:



Micro controller and 2.4GHz tranceiver chip:





Some image processing to help highlight the Atmel chip number:

[amyk]

The datecodes are from 2008 and that version looks quite hackable.

[lpc32]

I found out recently that Logitech's "Nano" receiver is not the same as their "Unifying" one. Nothing like artificial limitations.